| 摘要 |
PURPOSE:To obtain a thermoregulator of improved reliability and high precision which is free from an influence of a secular change, by exercising temperature control so that a difference in oscillation frequency between quartz oscillators differing in temperature characteristics reaches a desired value. CONSTITUTION:Oscillating circuit OS1 connected to AT-cut quartz oscillator QAT and oscillating circuit OS2 connected to Y-cut quartz oscillator QY are arranged in chamber A to be held at a constant temperature and their oscillation outputs are supplied to phase comparator PD. When oscillation frequencies fAT and fY of quartz oscillators QAT and QY are so set that fAT>fY, namely, when the temperature is lower than T0, a pulse of frequency DELTAf=fAT-fY is generated and when fAT<fY, namely, when the temperature is higher than T0, the output is held at ''0''. Therefore, when the temperature is lower than T0, heater H is put into operation to heat up the inside of chamber A. |
